deskutils/peaclock: Fix build

Fixed build issues:

• error: non-constant-expression cannot be narrowed from type 'std::1::chrono::duration<long long, std::1::ratio<1, 1> >::rep' (aka 'long long') to 'long' in initializer list [-Wc++11-narrowing]
• /usr/bin/ld: unrecognized option '-plugin'

Reported by: fallout